18F-FDG PET/CT in the Evaluation of Adrenal Masses

Abstract

Our purpose was to evaluate the performance of 18F-FDG PET/ CT, using data from both the PET and the unenhanced CT por-tions of the study, in characterizing adrenal masses in oncology patients.Methods:One hundred seventy-five adrenal masses in 150 patients referred for 18F-FDG PET/CT were assessed. Final diagnosis was based on histology (n 5 6), imaging follow-up (n 5 118) of 6–29 mo (mean, 14 mo), or morphologic imaging criteria (n 5 51). Each adrenal mass was characterized by its size; its attenuation on CT, expressed by Hounsfield units (HU); and the intensity of 18F-FDG uptake, expressed as standardized uptake value (SUV). Receiver operating characteristic curves were drawn to determine the optimal cutoff values of HU and SUV that would best discriminate between benign andmalignant masses. Results: When malignant lesions were compared with adenomas, PET data alone using an SUV cutoff of 3.1 yielded